Right up there as one of my favorite things about EPCOT are the all the random street acts. The JAMMitors are awesome! Check out the entertainment schedule insert when you enter the park - there are all kinds of good ones.
The guys play music outside Mission: Space on select days. (I sorta stalk them to be honest.) They're very thematic. For example, during the Garden Festival, they play with troughs on clay pots. Noisy for kids and smart for adults, check these guys out if you get the chance.